Premium vs Regular gas for track day

[GTP]

I'm sure there will be some strong opinions on this, but ... Is there any good reason not to run regular gas for track day?

That's what I have been running most of the time. I don't care about a little extra HP, and fuel cost for an out-of-town track weekend really adds up. I just don't know if there is any reliability risk to the engine with regular 87 octane gas.

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[nbjeeptj]

I run both regular and premium, depending if its a fun track day or a NASA TT weekend. For TT I want all the HP I can get, but the cost is just not worth it on a open track day. I have 7500ish track miles on my car and there has been no ill effect of running regular gas.

 

[sms2022]

The cost difference is negligible compared to the cost for an engine rebuild. I’d prefer to have some margin of error rather than have 87 octane gas in a 12:1 compression engine at 7400rpm and 220 degree cylinder head temps. That’s just me though.

 

[EFI]

87 is bad enough for the street, why would you want to run that in such an extreme environment as a track day where you're going WOT for minutes on end and everything gets so hot? It's not even for the power, but the knock control.

I wouldn't even consider it.

 

[ice445]

Absolutely not. With the temps seen on track you'll be using every bit of the timing retard available and have zero safety margin.

It will be fine until it's not lol

 

[ihasnostang]

i bought 6 gallons of 98 unleaded @ 12/gal for my last track day. they had 110 leaded for the same price but i wasnt sure if that was okay. but i'm tuned and turbo'd

 

[WildHorse]

I'm don't get how you can worry about such a small price difference for some peace of mind ? Like, are some of you's seriously that broke (and I ain't rich) ? Throw 91+ in it for Christ sakes.

 

[Less Weight]

Yeah, no offense, but this just seems dumb to take that chance. Penny wise; pound foolish.

But then again, we all shouldn't be so harsh on you. You don't know which is why you are asking.

 

[PSI]

I don’t track my car and it only gets premium.
Assuming .50 cents extra for premium, and 15 gallons of gas, that’s 7.50. Big deal, I can’t even get a six pack of cheap beer or a Big Mac meal for that anymore, I’ll take a few extra horsepower and a happier engine for 7.50.

 

[GTP]

Yeah, no offense, but this just seems dumb to take that chance. Penny wise; pound foolish.

I have run Shell 91 and I have run 87. Given all the expenses for tracking, I'm not trying to pinch pennies on gas. I just did not know if there is a risk, and according to the wonderful responses I am getting, apparently there is!

But then again, we all shouldn't be so harsh on you. You don't know which is why you are asking.

Exactly, and thank you.

 

[WildHorse]

Right in the owners manual:

"2.3L EcoBoost and 5.0L V8 Engines We recommend regular unleaded gasoline with a pump (R+M)/2 octane rating of 87. Some stations offer fuels posted as regular with an octane rating below 87, particularly in high altitude areas. We do not recommend fuels with an octane rating below 87."

^ This is a sales pitch

This is the key area:

"To provide improved performance, we recommend premium fuel for severe duty usage, such as trailer tow.""

^ this is for anything other than mundane driving, IE: spirited driving, racing.
Legalities and cause, nobody tows with a Mustang.

 

[GrayMater22]

I would always run at least 91 octane to prevent knock. I have always run 93 since I bought my car new, after I added a 114mm cai and tune, my car would cut timing (leaned out) at wot on the drag strip on 93, so I started adding race fuel to increase my octane to 98 octane. Now it can keep up with the air and no more issues at the track. Remember these are very high compression motors. Twenty years ago you would only find 12:1 compression in race cars.

 

[CobaltFilly]

I would always run at least 91 octane to prevent knock. I have always run 93 since I bought my car new, after I added a 114mm cai and tune, my car would cut timing (leaned out) at wot on the drag strip on 93, so I started adding race fuel to increase my octane to 98 octane. Now it can keep up with the air and no more issues at the track. Remember these are very high compression motors. Twenty years ago you would only find 12:1 compression in race cars.

When we first got our V6, the knock was absolutely *disgusting*. Turns out she had run 87 ever since the prior owner took delivery (first owner, ordered 2015, received 2016; I am second owner circa 2022). 5 miles after draining the 87 and replacing with 91 (from Costco), the knocking ceased and car felt normal.

 

[L8APEX]

If you are concerned about the price of gas, tracking isn't for you. Your tire and brake wear is far more expensive.

 

[EFI]

Given all the expenses for tracking, I'm not trying to pinch pennies on gas.

How much are you saving on a tankful of 87 vs 91...maybe $5?

How much are you spending on a full day track event...probably north of $500?

In the grand scheme of things, is $5 out of $500 really that big of a deal? Pack lunch instead of buying it at the track and you just saved yourself more than it cost to protect your $10,000 engine.

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